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does Prius have a timing chain tensioner

Discussion in 'Gen 2 Prius Technical Discussion' started by cnschult, Apr 9, 2012.

  1. cnschult

    cnschult Active Member

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    the reason I ask if the Prius has a timing chain tensioner is because the 04-09 corolla (gen 9) is famous for having oil leak through them due to an undersized o-ring.

    as expected mine was rusted and I wanted to stop the oil leak so I replaced mine in my corolla with an aftermarket one (SA King, not oem). I removed the old one, compressed the new one and put the hook on, I installed it with counterman's gasket sealer on the o-ring and inserted it, rocked the alternator bolt back and forth to release the hook but no noise, tried it several times to no avail so I just inserted it without compressing it, it didn't require much force to insert the tensioner plunger so i don't really see the point of having the hook. I started the engine and it made a nasty noise for a second and then it "appeared" to tighten up and has been running smooth ever since.

    so here are the questions:
    why does a tensioner need that hook if it was so easy to install w/o it engaged?
    should I be worried about that one second of nasty noise?
    does the Prius having a timing chain tensioner?
    if so, does the Prius one leak oil as well and need replacement?

    a search brought nothing up so i'm assuming the answers to at least one of the last two questions is NO but I'll wait for the experts to chime in.
     
    #1 cnschult, Apr 9, 2012
  2. dogfriend

    dogfriend Human - Animal Hybrid

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    If it has a timing chain (it does) then it will have a tensioner. It may not be the same design as the Corolla (at least for a Gen 1 & 2) because the basic engine design is not the same.

    I have not seen any complaints regarding the timing chain or tensioner on this forum.
     
    #2 dogfriend, Apr 9, 2012
  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    #3 JimboPalmer, Apr 9, 2012
  4. Mike500

    Mike500 Senior Member

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    A timing chain does not really need a tensioner like a timing belt. Even with a timing belt, there is very little tension needed on a cogged belt as compared with a belt driven by friction contact like a regular fan belt.

    The timing change uses a "guide" over which the "non-tension" trailing links of the chain slide over the guide. The crankshaft sproklet actually applies tension to the chain, which pulls the sprocket gears on the crankshaft. The "guide" is actually on the part of the chain that pulls no sprocket and is only pulls itself with just enough tension to overcome its own inertia to keep it in motion.

    Engine oil lubricates the chain as is rides over the guide. Since there is very light contact with the guide, there is very little friction and wear on the guide. On that account, the contact surface of the guide is very long lived as the guide is made of a polymer with a very low friction coreficient. It is likely POM (Delrin), or in some cases, UHMW PE.
     
    #4 Mike500, Apr 9, 2012
  5. David Beale

    David Beale Senior Member

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    It has a chain tensioner that pushes on the chain guide. It uses oil to provide the tension. As stated above, there have been no reported issues with the tensioner.
     
    #5 David Beale, Apr 9, 2012
  6. cnschult

    cnschult Active Member

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    thanks guys, turns out I was supposed to turn the crankshaft to build compression in engine to release the piston, not the alternator, who knew you couldn't trust everything you read on the internet? Toyo Tech assured me I was okay for that one second of ugly noise and that my engine and chain are both fine.
     
    #6 cnschult, Apr 14, 2012
    Tanman likes this.
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